What type of reaction occurs when an acid reacts with a base?

When an acid reacts with a base, the main type of reaction that occurs is a neutralization reaction. In this process, the acid donates protons (H⁺ ions) while the base provides hydroxide ions (OH⁻). The combination of these ions forms water (H₂O), and often produces a salt as a byproduct. This is a classic example of how acids and bases interact according to the Brønsted-Lowry and Arrhenius definitions, showcasing the characteristic property of neutralization.

This reaction is fundamental in chemistry, as neutralization reactions can be used to determine the concentrations of acids and bases, regulate pH levels, and understand various chemical processes in biological and industrial settings. The resultant solution has a pH that is closer to neutral compared to the original acid and base solutions.